Apparatus for inspecting cigarettes or the like

ABSTRACT

An apparatus for examining an end of a cigarette or the like to determine whether packed tobacco is present to substantially the edge of the cigarette wrapper. In accordance with the invention there are provided means for directing a narrow collimated beam of light, preferably a laser beam, along the axis of the cigarette and toward the end to be examined. A photodetector is positioned and oriented to receive light emanating from at least a portion of the wrapper surrounding said end. Further means, responsive to the output of the photodetector, are provided for generating an occurrence indication when the photodetector output exceeds a predetermined threshold level. In a preferred embodiment of the invention, means are provided for enabling the generating means only when a cigarette is present at a specified inspection position.

United States Patent [191 Gugliotta et a1.

[ APPARATUS FOR INSPECTING CIGARETTES OR THE LIKE [75] Inventors: George Gugliotta, Ridgefield;

Anthony J. Raimo, Waterbury, both of Conn.

{73] Assignee: Laser Sciences, Inc.

[22] Filed: Apr. 6, 1973 [21] Appl. No.: 348,517

[52] US. Cl 2 50/223 R, 250/572, 356/237, 7 209/111.7 [51] Int. Cl. G0ln 15/08 [58] Field of Search 250/219 DF, 221, 222, 223, 250/572; 209/111.7; 356/239-241, 237;

Rottmann 356/240 X Black et a1 209/1 1 1.7

Primary Examiner-Wa1ter Stolwein 57] ABSTRACT An apparatus for examining an end of a cigarette or the like to determine whether packed tobacco is present to substantially the edge of the cigarette wrapper. In accordance with the invention there are provided means for directing a narrow collimated beam of light, preferably a laser beam, along the axis of the cigarette and toward the end to be examined. A photodetector is positioned and oriented to receive light emanating from at least a portion of the wrapper surrounding said end, Further means, responsive to the output of the photodetector, are provided for generating an occurrence indication when the photodetector output exceedsa predetermined threshold level. 1n a preferred embodiment of the invention, means are providedfor enabling the generating means only when a cigarette is present at a specified inspection position.

3 Claims, 3 Drawing Figures J SCANNER 34.0 SURFACE R SCAN P ocz ms GATING SS SIGNAL 13 1 H5 A -l THRESHOLD H REJECT oarscron ACTIVAI'OR GATING SIGNAL Fmsmenm 21 m so SCANNER 1 DRIVE GATING SIGNAL 45 THRESHOLD REJECT DETECTOR ACTIVATOR Lam;

GATING SIGNAL Fig. l.

SC PROCE SURFACE AN SSING APPARATUS FOR INSPECTING CIGARE'I'IES OR THE LIKE BACKGROUND OF THE INVENTION This invention relates to inspection systems and, more particularly, to an apparatus for examining the end of a cigarette or the like to determine if tobacco is present to substantially the edge of the wrapper.

The manufacture and packaging of cigarettes is a largely mechanized high speed operation which doe not lend itself well to manual/visual inspection of the product. There are various types of defects which can occur in the manufactured product. Even with improved techniques, a certain number of defects are unavoidable. The defects may occur in a cigarette wrapper paper which can develop a small hole, pick up a dirt spot, or be incorrectly joint to itself. The detection of these types of defects requires some sort of surface examination. To our knowledge, no satisfactory technique for such examination is presently available to the cigarette industry. 7

Another type of defect results when an end of a cigarette is loosely packed or empty. This condition, appropriately known as a loose end, is also difficult to detect during high speed manufacture. One suggested detection technique involves a reciprocating pressuresensitive probe which feels the end of each cigarette as it passes an inspection position on the production line. When a low contact pressure is sensed, the offending cigarette is considered a reject and is automatically removed from the production line. A problem with this technique is the difficulty of taking an accurate pressure measurement when the precise longitudinal location of each passing cigarette and is not determinable to a close tolerance. A further problem is that the probe, by interacting with the tobacco, can actually cause the condition it is trying to detect; i.e., it can loosen the tobacco at the cigarette end.

Accordingly, it is an object of the present invention to provide a system which inspects cigarettes for defects and which can determine the presence of loose ends accurately without touching or distrubing the cigarettes.

SUMMARY OF THE INVENTION The present invention is directed to an apparatus for examining an end of a cigarette or the like to determine whether packed tobaccois present to substantially the edge of the cigarette wrapper. In accordance with the invention there are provided means for directing a nartailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 there isshown a diagram of an system 10 for automatically inspectingcigarettes or the like. The invention is particularly applicable to the inspection of common cigarettes, but can be employed for the inspection of certain other-filled wrappers having characteristics similar to cigarettes. The term cigarettes or the like" is thus generically defined in this manner.

In the illustrative embodiment of FIG. 1, cigarettes are carriedin the spaced grooves 11 of a moving belt 12 which proceedsin a direction perpendicular to the plane of the paper and depicted by an arrow 13. The three cigarettes shown are designated by the reference numerals14, 15 and 16. The cigarette 14 is presently located at an inspection position while the cigarettes 16 and 15 have just successively passed through the inspection position. It will be appreciated that the belt is merely a representative means for transporting the cigarettes past the inspection position and various alternate transport means may be suitable.

A laser 20, preferably a low-power device such as a helium-neon gas laser, generates a laser beam 21 which is split into separate beams 22 and 23 by a beam splitter 24. The beam 22 is employed in a subsystem called a surface scan subsystem" which is used to examine the surface of the cigarette wrapper for defects. The surface scan subsystem includes an optical scanner 30 which is driven by suitable activating means (not row collimated beam of light, preferably a laser beam,

along the axis of the cigarette and toward the end to be examined. A photodetector is positioned and oriented to receive light emanating from at least a portion of the wrapper surrounding said end. Further means, responsive to the outputof the photodetector, are provided for generating an occurrence indication when the photo-detector output exceeds a predetermined threshold level. In a preferred embodiment of the invention, means are provided for enabling the generating means only when a cigarette is present at a specified inspection position. J

Apparatus is also disclosed for examining the wrapper surface of the cigarette.

Further features and advantages of the invention will become more readily apparent from the following deshown), focusing optics 31, photodetector means 32, and processing circuitry 33. In operation, the beam 22 is scanned longitudinally over the surface of the cigarette as depicted by the beam 22' and the adjacent displaced beam shown in dashed line. The light reflected from the-cigarette is received by the photodetector means 32 whose output is coupled to processng circuitry 33. As the spot of laser light moves across the surface of the cigarette some light is reflected toward the photodetector 32. The amount of light received by the photodetector 32 will depend on properties of the surface such as reflectivity or roughness. Reflection from normal cigarette paper is substantial, but reflection from a hole in the paper or a dirt spot will be relatively small. The processing circuitry 33 detects a prescribed decrease in the output of the photodetector 32 and generates a reject signal on a line 33A.

A gating signal is also received by the processing circuitry over a line 34A. This signal, which acts as an enable, is present only when a cigarette is in the prescribed inspection position and the beam incident thereon. Thus, the generation of extraneous reject signals is minimized.

The beam 23' is employed in an end inspection subsystem which'is utilized to detect the presence of a -loose end condition. The end inspection subsystem a beam diameter of about 0.25 inch being found suitable.

We have discovered that a tightly and properly packed good cigarette end responds quite differently to the axial light beam than a loose. end or one which is void of tobacco. When the beam is incident on a loose end the white wrapper paper surrounding the end is found to glow. For example, when a helium-neon laser having a visible energy at 6,328A in the red portion of the visible spectrum is utilized, the loose end can be observed to glow red. On the other hand, when the beam is incident on a good. end the end exhibits little if any noticeable glow. These phenomena are believed to result, at least in part, from the light-absorbing and/orscattering characteristics of the tobacco. in the illustration of HG. 2A, the light beam entering a loose end is reflected or scattered toward the wrapper paper near the edge of the cigarette, as is depicted by the small arrows. Some light is, of course, absorbed, but sufficient light is received at the paper to make it glow. in effect, the paper collects the light. H0. 23 shows the situation for a go end where most of the light is either absorbed by the more plentiful tobacco strands near the end or is scattered away past the edge of the paper. In such case the paper is not found to glow appreciably.

A photodetector 41 is positioned and oriented to receive light emanating from the wrapper surrounding the end of the cigarette being examined. A light filter 42, having a pass characteristic which matches the laser wavelength, is interposed between the cigarette end andthe photodetector. The use ofa monochromatic beam in conjunction with the filter is advantageous in minimizing the possibility of ambient light extraneously exciting the photodetector. The output of the photodetector is coupled through suitable amplification and filtering circuitry 50 to a threshold detector 43. The threshold detector generates a reject signal on a line 43A when the photodetector output exceeds a predetermined threshold level This threshold level can be determined empirically by selecting an end having the minimum desired degree of looseness and then observing the photodetector output level which results.

The threshold detector is enabled by a gating signal 3413 which is present only when a cigarette is in the prescribed inspection position.

The provision for a gating signal is not strictly necessary but it ofiers further insurance against the generation of extraneous reject signals. There are various possible. ways to produce the gating signal 348. For example, an auxiliary laser beam can be utilized to determine when the object to be examined has entered the inspection position. Alternatively, the belt 12,. or'other suitable carrier, may be equipped with a positional synchronizingmeans which tracks the physical position of each cigarette. For'example, each groove 11 on an endless belt 12 can be in registration with a sprocket (not shown) which drives the belt. In such case, a counter (not shown) synchronized with the rotational position of the sprocket knows the position of each groove on the belt and the gating signal can be. derived therefrom.

The reject signals onlines 33A and 43A are coupled to a reject activator 45 which typically comprises delay means and a solenoid. The solenoid output activates an air nozzle 46 which is positioned at a fixed distance downstream from the examination position. With the belt 12 operating in a periodic cycle, the delay means in the reject activator is adjusted to correspond to the transit time between the inspection position and the position of air nozzle 46. Thus, any cigarette which causes a reject signal arrives at the nozzle 46 in time to be blown off the assembly line. Alternate means of effecting rejection can, of course, be employed. For example, if the individual grooves 11 are being tracked by a counter, as described above, the number associated with the groove holding a defective cigarette can be marking means responsive to the reject signals. A tiny spot of dye is immediately applied to a defective cigarette. At a later stage, the dye spot is automatically detected so the offending cigarette can be segregated.

The invention has been described with reference to a particular embodiment but it will be appreciated that variations within the spirit and scope of the invention will occur to those skilled in the art. As an example, the reject signals may be coupled to a counter which triggers an alert buzzer orlight when the number of rejects per unit time exceeds a given limit. In such case a faulty production mechanism can be quickly recognized.

We claim:

1. in a system where cigarettes or the like. are transported on'a carrier past an inspection position, an apparatus for examining'the'wrapper surfaceof the cigarette located at the inspection position and for examini ing the end of the cigarette located at the inspection position to determine whether packed tobacco is present to substantially the edge of the cigarette wrapper,

reflected from the cigarette; means responsive the output of said first photodetector for generating a first occurrence indication when the output of said photodetector falls below a prescribed level; I

means for examining the end of the cigarette located at the inspection position to determine whether packed tobacco is present to substantially the edge of the cigarette wrapper, said means comprising;

means for directing a narrow beam of light from said laser beam along the axis of the cigarette and toward the end tobe examined; i I

a second photodetector positioned to receive light emanating from at least a portion of the wrapper surrounding said end when said end is substantially void of tobacco and said narrow beam enters said end causing the outer surface of the wrapper portion to glow; and

means responsive 'to the output of said second photodetector for generating a second occurrence indication when the output of said second photodetector exceeds a predetermined threshold level.

2. The apparatus as defined by claim 1 further com- 5 prising means for enabling the generation of said first and second occurrence indications only when a cigarette from the carrier. 

1. In a system where cigarettes or the like are transported on a carrier past an inspection position, an apparatus for examining the wrapper surface of the cigarette located at the inspection position and for examining the end of the cigarette located at the inspection position to determine whether packed tobacco is present to substantially the edge of the cigarette wrapper, comprising: means for generating a laser beam; means for scanning the laser beam over the wrapper of the cigarette at the inspection position; a first photodetector positioned to receive the beam reflected from the cigarette; means responsive the output of said first photodetector for generating a first occurrence indication when the output of said photodetector falls below a prescribed level; means for examining the end of the cigarette located at the inspection position to determine whether packed tobacco is present to substantially the edge of the cigarette wrapper, said means comprising; means for directing a narrow beam of light from said laser beam along the axis of the cigarette and toward the end to be examined; a second photodetector positioned to receive light emanating from at least a portion of the wrapper surrounding said end when said end is substantially void of tobacco and said narrow beam enters said end causing the outer surface of the wrapper portion to glow; and means responsive to the output of said second photodetector for generating a second occurrence indication when the output of said second photodetector exceeds a predetermined threshold level.
 2. The apparatus as defined by claim 1 further comprising means for enabling the generation of said first and second occurrence indications only when a cigarette is present at the inspection position.
 3. The apparatus as defined by claim 2 further comprising means responsive to said first and second occurrence indications for automatically removing the cigarette from the carrier. 